Hello from Russia!
Sorry for the bad translation - used translate.google
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Disassembled completely amplituner Cabasse that we have:
the processor M30879FLAGP (M32C)
audio SAF7730HV/317
pre-amplifier (op-amp) main (4ch) NJM2060, center/subwoofer NJM4558
Amplifiers:
main (4 channel) TDA8592J (maximum 45-50W x 4Ch, about 21W at minimal distortion), the Central channel TDA7396 (maximum 40-45W, about 19W with minimal distortion).
the differential output on the subwoofer through the NJM4556.
Studied a little diagram:
Subwoofer output - the output is. The signal on the block enable external amplifier is missing, but the clip settings include the desired option and the enable signal of the external amplifier on the block appears.
Began to search for the reason why cabasse produces poor sound. Desoldering pre-amplifier (op-amp) on NJM2060, measured parameters of parts modeled scheme in Multisim. The simulation showed that the frequency response is almost flat, slightly swamped at the edge of the sound range, a bit phase scrolls (about 60 degrees) but all within reason. It turns out mainly in response to the signals on front/back/center/subwoofer, audio controls (Datasheet not found).
Began to look further found that food shelter and "average" little point "floats" on the frequency of the signal so much "floating" power supply ic. Check capacitors on nutrition showed that 2 (C514 - 3300uF/16V and C352 - 1000uF/16V) running on power ic has lost about 10% of its capacity, the rest in norm. Replaced both on 3300uF/16V so-called Low ESR with temperatures up to 105°C (less impossible, radiator power ic in an outdoor environment under load is heated to 65-70°C, in a closed variant of 80°C, the capacitors are inside the radiator and well-warmed up, so old already "dry") and additionally hung in parallel 0.1 μf. Also increased the capacitors on the power of the OS, +9V, native is MC parallel soldered on another 100uF/25V Low ESR (established in the area IS303 - njm4556), the average point at the shelter (about +5 V) native (C337) is 10uf, soldered in parallel of the same capacity. Soldered power +9V and +5V blocking capacitance 0.1 µf directly at the feet of the existing OS.
Tests have shown, amplituner started producing good sound (in the doorway native speakers stopped wheezing (in the settings of the bass made +2, high +1, balance before/ass move one back, LOUD, the sound is clear, deep, appeared on the scene and soft bass at high volumes the bass hits you in the stomach
. Connect a separate subwoofer showed the need exists. (if it is reasonable to listen to music). The plans were changing the speakers in the doors for a better - but, over time, to change change your mind, native cabasse (Panasonic) good...
Later, he added another 2200uF/16V Low ESR capacitor on the power supply IC with a blocking 0.1 µf (deleted blocking C515, was installed in his place 2200uF/16V, with the reverse side of the card pipav parallel remote blocking capacitor C515). The total capacity is obtained cf. Replaced bushing capacitors 0.22µf (front C333, C334, rear C335, C336) going to the inputs of the main power IC, 0.47uF. The sound of the bass became more intense, up almost to maximum volume, "dirt" in no sound.
Thinking to increase the power output stage to 17V with a simultaneous increase in the area of the radiator - this will increase not distorted (at minimal distortion) power up to 30-32 watts at 4ohm (c 65-68 W maximum power).
ps
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